<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <button @click="add">+</button>
        <h1>{{num}}</h1>
        <button @[event] = "sub">-</button>
    </div>
</body>
<script src="https://cn.vuejs.org/js/vue.js"></script>
<script>
    let vm = new Vue({
        el:"#app",
        data:{
            num:888,
            event:"click"
        },
        methods:{
            add:function(){
                this.num += 1;
            },
            sub:function(){
                this.num -= 1;
            }
        }
    });
</script>
</html>